The present invention relates to surgical devices and more particularly to surgical devices constructed for endoscopic injection therapy.
Endoscopic injection therapy was first used to stop certain types of internal bleeding as early as 1939. This therapy method involves the injection of a chemical agent through a needle injector into or around a bleeding site within the human body to stop excessive bleeding. A variety of other applications for endoscopic injections have been developed, including biliary duct treatments.
Bile is a bitter yellow or greenish liquid that is secreted by the liver into the gastrointestinal tract. Bile aids in the digestion of fats and enters the stomach through the bile duct. In some cases, the bile duct can become blocked. This condition causes jaundice and can lead to further complications. Conventional solutions to this problem have included using an endoscopic surgical tool to cut open a portion of the bile valve. Although this procedure typically is successful in opening the valve sufficiently for bile flow, excessive bleeding is a common and dangerous complication with this and other similar procedures.
Procedures for treating the bile duct blockage, as well as treating subsequent bleeding caused by the procedures, have been limited by the relative inaccessibility of the valve. In a typical endoscopic procedure to stop excessive bleeding, a surgeon uses an endoscope to visualize the bleeding site, and then passes the needle through the instrument channel until it reaches the distal end of the scope. The surgeon then extends the needle into a subject to deliver a chemical agent. In a biliary injection procedure, the target area is the bile duct and areas adjacent the cut location.
The outlet port of the bile duct is located at an undesirable angle, making access difficult by conventional endoscopic injection therapy techniques. Although surgeons in most cases can maneuver a scope into a desired position, extending the needle in order to inject the chemical agent is made prohibitively difficult by the bile duct location.
When the distal end of a conventional endoscope is bent acutely in order to access the bile duct, the kinetic friction on internally moveable parts increases. Using conventional injection therapy devices within a scope, surgeons experience difficulty in extending needles prior to injecting the chemical agent. Even if a surgeon can successfully extend the needle, there is an equal difficulty in retracting the needle after injection of the chemical agent. In a severe case, the surgeon may be forced to withdrawn the endoscope with the needle still partially extended out of the endoscope. This undesirable condition can cause injure to the patient.
Consequently, a cut made in the bile duct is typically clotted with conventional media to stop bleeding. This technique is not without failure. About half of the deaths due to post-surgical complications of bile duct treatments are caused by excessive bleeding.
The present invention provides a new and improved therapeutic injection device for use in endoscopes that is particularly beneficial in biliary endoscopes for hemorrhage control. The device features very low internal kinetic friction enabling ease of needle extension. Moreover, the design allows extreme flexibility and low friction needle extension and retraction at acute angles near the tip of the device. The device also features precise and repeatable operational features in regard to the length of the device. The invention can be modified for use with a variety of endoscopes, including a duodenoscope having side viewing optics and a side exiting instrument channel.
In an illustrated embodiment of the invention a surgical device for use in endoscopic injection therapy is provided including a support body, a motion transmitting unit, an agent delivery system and a guide housing.
The motion transmitting unit includes a first end portion proximal to the support body and a second end portion remote from the support body. The motion transmitting unit is movable relative to the support body.
The agent delivery system includes a needle and structure defining a conduit. The needle is disposed remote from the support body. The needle has a hollow elongated body, a first end for extending into a subject, and a second end fixed to the motion transmitting unit. The conduit extends between the support body and the needle.
The guide housing for guiding the needle has a flexible elongated body and includes an end portion proximal to the needle, an internal elongated passage and friction reducing material. At least a portion of the motion transmitting unit adjacent the needle is slideably housed within the guide housing.
The motion transmitting unit may include an elongated flexible tube forming the conduit. The motion transmitting unit may include a first member constructed from hypodermic needle stock and a second member constructed from flexible tubing.
The guide housing may be constructed from flexible tubing defining an internal diameter lined with a friction reducing material. The guide housing may be constructed from a helically wound wire spring forming an internal elongated passage, wherein at least a part of the wire is coated with a friction reducing material. The friction reducing material may be Polytetraflouorethylene.
The agent delivery system may include a return mechanism having a spring for returning the needle to a non-extended position within the guide housing.
The guide housing may be conditioned prior to use, whereby a length of the guide housing remains essentially fixed during routine use such that the needle is disposed within the guide housing when in a non-extended position.
A method of making a surgical device including the step of conditioning the guide housing prior to use is also disclosed. The conditioning may include repetitively coiling the guide housing in an alternating pattern until the initial length shortens to essentially the desired length. Alternatively, the conditioning may include axially compressing the guide housing under force until the initial length shortens to essentially the desired length.
The present invention offers advantages over devices available in the prior art. The device offers low internal kinetic friction allowing ease of needle extension and retraction while the distal end of the scope is bent at acute angles. The device further offers the surgeon increased needle control and range of movement outside of the endoscope. The increased range of needle movement increases available target areas within the subject, while at the same time, decreasing procedural performance time. In addition, the device also features precise, repeatable and safe operational features in regard to the length of the device.
Further features and advantages of the invention will become apparent from the following detailed description of an illustrated embodiment made with reference to the accompanying drawings.